e eco. from spending time together, to spending your lives together, chevy runs deep. this is "world news" -- tonight, driving blind. a super fog descends on the freeway. as it's happening. >> tell me what happened. >> another accident, another hasn't. >> we put a clock on the front-runner mitt romney to see how long it takes him to slam his rival. preventing heart attacks. big news today about statins and who should be taking them. and sharper brains. we have the surprise new research showing middle-aged brains can work better than young ones. is 53 the smartest age of all? good evening.

tonight, we begin with the deadliest crash on an american highway in 20 years. and a warning for every driver in the country. there was a fiery pileup in florida when a sudden blinding super fog rolled in. mist and smoke. take a look at this picture. through a front dashboard window, you can see the hood of the car but absolutely nothing else. and there are those newly released 911 tapes taking us inside the fog with the drivers who could hear the collisions all around them. abc's matt gutman is in florida tonight. >> reporter: tonight, the very moment of impact. >> what is going on? >> reporter: in these just released 911 tapes, you can hear the apocalyptic scenes unfold. one estimates the cars were going as fast as 80 miles an hour straight into the wreckage. >> what just happened? >> another hasn't. another accident.

and that was a truck. >> reporter: in this mash of mangled steel and bodies, at least ten dead, 20 hurt. skeletons of 18 wheelers and cars smoldered for hours after the pileup on i-75 early sunday morning south of gainesville, florida. >> you hear cracks and thuds and bumps. you just hear the sound of metal. >> reporter: stephen was in a car wedged between two semis. >> you hear people crying. you hear people, you know, just basically asking why. the fog was so dense that, you know, you could literally get out of the car and hold up your hand, you wouldn't see it. >> reporter: authorities blame the carnage on what's called a super fog. the combination of ash from a nearby brushfire mixing with water particles creating a wall of fog that's completely impenetrable. it forms quickly. visibility drops to near zero. you get a feel for how dangerous it is from this clip at local station bay news 9 after similar

con i dids cost four lives in 2008. >> you can't see me anymore. >> reporter: sunday it was so thick rescuers had to locate victims by their screams. authorities temporarily closed the road following two earlier accidents on saturday. then reopened it. minutes later, in the station. >> roadway appeared to be clear and able to be navigated and then it could change just in an instant. >> reporter: 36 hours later, authorities are still trying to identify the victims and also the sequence of collisions. they're also trying to figure out why the decision was made to reopen that road. a very dangerous one they say. authorities say if you find yourself on such a road, crack the window. even if you can't see the cars in front of you, you might be able to hear them. >> and, again, the sound of those drivers with those 911 calls, matt, what have you learned tonight about what caused that smoke? >> reporter: well, the authorities are saying it might have been arson. they've ruled out any lightning strikes happened or there was a controlled burn. authorities are telling us if a suspect is found to have started

that fire, could be charged with multiple counts of manslaughter, diane. now, 24 hours till the results of "your voice, your vote" in the florida republican primary. where mitt romney has opened a 14-point lead over newt gingrich who began to sink in the polls after romney launched attack after attack. abc's david muir is in florida. he says romney is not letting up tonight. david. >> reporter: diane, good evening to you. fueled by those new poll numbers, we flew with governor romney today. he sensed a week and a half ago south carolina was not going to go his way. if that's the case come tomorrow, you could point to an aggressive switch in strategy. tonight, this fight in florida is far different. just weeks ago, it was not uncommon romney would deliver an entire stump speech without

mentioning these two words, newt gingrich. today, romney walked on to the stage and we counted, just 33 seconds before romney took aim. >> speaker gingrich wasn't very happy with the debates though. he said after the first debate he didn't do well because the crowd was so quiet. >> reporter: and then late today outside tampa, 44 seconds in. >> speaker gingrich, he's not feeling very excited these days. i know, it's sad. he's been flailing around a bit. >> reporter: to give you an idea of what it's like for anyone watching tv in florida, in jacksonville, just today, during the news, five ads in just 15 minutes, all for romney. including that controversial ad using a 1997 report from then anchor tom brokaw on speaker gingrich's ethics violations airing not once, not twice, three times in 15 minutes. it is an aggressive shift from the romney team after that stunning loss to gingrich in south carolina. in florida, clearly outspent, gingrich today vowed to stay in the race through the convention.

as we flew with governor romney to tampa, this is how he reacted to that. >> that's usually an indication that you think you're going to lose. when you say i'm going to go on, no matter what happens, that's usually not a good sign. >> reporter: today gingrich says the delicate map will hardly be sealled after florida. anand with help from calista wi his hair, gingrich blasted the front-runner in an interview with john karl. >> that's where you think -- what you think romney is doing, he's buying the election? >> of course. >> where's he getting money? >> wall street. >> reporter: gingrich told our john karl he's just getting started. this could be an incredible financial mountain. romney and his allies have outspent gingrich by some $5 million. that's 4 1/2 times as much. we'll see what happens. >> george stephanopoulos joins us. can romney's money close this out? >> not easily and not fast. but they're coming off the best week in their campaign, no question about it, diane, but

even as the romney team anticipates a pretty comfortable win tomorrow night, they are resigned to a long hard slog to get the delegates they need to wrap up this nomination. >> do you think newt gingrich can come back again, again? >> it has never happened before. we've never seen a candidate come back not once, not twice, but three times from basically being dead, politically dead in this campaign. he does have a lot of incentive to stay in. if he gets a plurality in five states, he can put his name and nomination in at the convention and have leverage. a lot of incentive to go on. >> there must be so many people calling him and saying, come on, come on, pull out, make it a clear shot. anybody able to change his mind? >> maybe his wife, that would be about it. because right now i think he sees himself, newt gingrich, leading a movement against the establishment of the republican party. most of the establishment, diane, has weighed in against newt gingrich.

>> okay, george. tomorrow night, you and i will be right here. we'll be joined by our election team at abc news for the big results as they come in. hope to see you tomorrow night. one more note from the campaign. republican rick santorum is back on the trail tonight after spending the weekend in philadelphia to be with his 3-year-old daughter bella who was in the hospital with pneumonia, a complication from the rare genetic disorder she has called trisomi 18 which is in the constellation of genetic disorders that includes down syndrome. santorum has said his valiant daughter bella is now doing much better. and we move on to washington watchdog. another revelation causing outrage about mortgage giant freddie mac, which is backed with taxpayer dollars. the agency we thought was working to refinance mortgages for struggling homeowners was also making a profit by betting against some of those homeowners. abc's jim avila has the story. >> reporter: when freddie mac

went nearly bankrupt, american taxpayers bailed them out. but when jay and bonnie silverstein like many american homeowners, asked to lower their payments, the answer was no. >> we are in financial jail. >> reporter: if they could have that rate reduced to 4%, the current average, they'd save $500 a month. but freddie mac, the government-run mortgage giant, that's supposed to make it easier to own a home, won't let them refinance. >> it just flies in the face of common sense. >> reporter: and it makes them angry, because it turns out freddie mac is making money from homeowners like the silversteins, by keeping them stuck in higher interest loans. a joint investigation by national public radio pro publica has found freddie mac has invested a billion of its own monet betting against those loans coming down. >> when the homeowner refinances, freddie mac now loses.

>> reporter: legal, but critics now call it a clear conflict of interest. >> what you're doing is telling homeowners, "gee, i'm going to stop you from refinancing, and it's going to be profitable for my portfolio." >> reporter: is it fair to say they set the house rules and then they bet? >> one bond trader said to us, it's like betting on the super bowl and then shooting tom brady in the ankle. >> reporter: freddie mac says there's a wall between the people investing freddie's money and the people making credit decisions. and while they won't comment on the alleged conflict, the company points out that refinancing makes up 80% of its business. the silversteins are among the 20% still paying the higher rates, and making freddie mac more money. jim avila, abc news, new york. another day of fierce violence if syria as the world watches a very unstable situation. government troops pushed opposition forces away from the edge of the capital city damascus, as another mideast strongman, bashar al assad,

tries to hold on to power. the american woman rescued from pirates by the intepid navy s.e.a.l.s will spend the night in the u.s. tonight. held by three months by pirates in somalia. we're getting a glimpse of her life as a captive. i had a chance to speak by phone with her father, who was waiting for her arrival, and wanted to thank the navy s.e.a.l.s and everyone who brought joy to this family tonight. >> we're doing well as a family. her yet, so today's the big day. >> reporter: what is it you want most to say to her? >> i love you. you know? face to face again. >> reporter: it must have been terrifying. >> yeah, i mean, these guys were armed. and we say pirates and that almost gives them a cartoonish feel, i think, sometimes, but they're just basically gangsters. >> reporter: and her health? her health okay? >> it's okay from what i understand.

she has some issues, but nothing life threatening at this point. i do know that they moved her very frequently. she's also into natural food and a vegetarian, and i understand her primary diet was camel milk and goat meat. >> -- incredible men and women in uniform to do what they do. >> we just can't thank them enough for risking their lives, and i wanted to thank president obama for just having the fortitude to make the decision to okay the action. the fbi -- can't thank them enough. and also, jessica's organization was there. they stood behind her the whole time. >> reporter: i can only imagine the moment that she's there in front of you. >> yeah, it's going to be good. >> a very grateful family tonight. and still ahead on "world news," a major study, changing

the way we think about statins and who should be taking them. and the secret is out about that mysterious super bowl commercial everyone is talking about. >> how can i handle work on a day like today? i love that my daughter's part fish. but when she got asthma, all i could do was worry ! specialists, lots of doctors, lots of advice... and my hands were full. i couldn't sort through it all. with unitedhealthcare, it's different. we have access to great specialists, and our pediatrician gets all the information. everyone works as a team. and i only need to talk to one person about her care. we're more than 78,000 people looking out for 70 million americans. that's health in numbers. unitedhealthcare. to help protect your eye health as you age... would you take it? well, there is. [ male announcer ] it's called ocuvite. a vitamin totally dedicated to your eyes, from the eye-care experts at bausch + lomb.

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as well as men. tonight, abc's dr. besser tells us for the first time a study proves statins are as effective in preventing heart attacks in women as well as men, including some who have not been getting help. >> reporter: renu kohli is exactly who they're talking about. 53 years old with the classic risk factors for heart disease. >> my cholesterol has always been high. my father died of a stroke and my brother had a massive heart attack. >> reporter: but her doctor didn't prescribe a statin, a drug used to lower cholesterol and heart disease risk. >> she said, oh, you could bring it down using diet and exercise. >> reporter: renu's daughter, payal, a cardiology fellow in boston, wanted her mom on a statin. >> i have to say, i felt incredibly frustrated that she wasn't getting treated in the appropriate way, despite having risk factors. >> reporter: today's study may change doctors' minds. it's the first proof that statins work just as well in women like renu as they do in men.

statins reduce the risk of heart attack or stroke by 19 percent, by lowering cholesterol and reducing inflammation. bringing relief to a denver mom who can finally follow her daughter's advice. >> i think my daughter saved my life. if it wasn't for her pushing this statin on me, i might have been the same for me as it was for my brother who had a heart attack while being on a treadmill. >> her daughter saves her life. what on earth took so long to study women and statins? >> i know, it's surprising. but none of the stud i weres that were done had enough women in them individually to answer the question. they had to combine them together to answer this. >> so what do you recommend for women going in to see the doctor? do you ask for consideration? >> well, you don't ask for a statin but you have to look at your overall risk because it's not just about cholesterol. if you're obese. if you have diabetes. if you smoke. if you have high blood pressure. more importantly if there's a family history of heart disease, you have to be talking about this and getting treatment, regardless of your gender. >> reminder, again, the number

one killer of women too. >> number one. >> heart disease. thank you, rich besser. and still ahead, that super bowl spot everyone is talking about is ferris bueller taking another day off. their own futu. how they'll live tomorrow. for more than 116 years, ameriprise financial has worked for their clients' futures. helping millions of americans retire on their terms. when they want. where they want. doing what they want. ameriprise. the strength of a leader in retirement planning. the heart of 10,000 advisors working with you one-to-one. together for your future. ♪ the amazing alternative to raisins and cranberries together for your future. with more fiber, less sugar, and a way better glycemic index. he's clearly enjoying one of the planet's most amazing superfruits. hey, keep it down mate, you'll wake the kids. plum amazins. new, from sunsweet.

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ask your doctor about symbicort. i got my first prescription free. call or click to learn more. [ male announcer ] if you can't afford your medication, astrazeneca may be able to help. forty years ago, he wasn't looking for financial advice. back then he had something more important to do. he wasn't focused on his future. but fortunately, somebody else was. at usaa we provide retirement planning for our military, veterans and their families. now more than ever, it's important to get financial advice from people who share your military values. for our free usaa retirement guide, call 877-242-usaa. now, we'll take you diving under water to see the new view tonight of that capsized cruise ship off italy. in an eerie echo of the titanic, you see bikes tied to the ship's railings and dining room tables

and dishes caught in the nets. the death toll is now 17 and officials say it could take most of the year to remove the wreckage. and a tribute to the women who braved so much cleaning houses so their chirp could have a future. last night, the screen actors guild gave top awards to the stars of the help. octavia spencer and viola davis, who spoke emotionally about the message of quiet heroism inside that film. >> the stain of racism and sexism is not just for people of color or women. it's all of our burden. all of us. i don't care how ordinary you may feel. we all of us can inspire change, every single one of us. thank you. >> and viola davis is nominated for an oscar at next month's academy awards. everyone loves the super bowl ads. tonight the secret is finally out on the one featuring actor matthew broderick. this morning, it was just a tease. was it possible the high school

renegade ferris bueller is coming back? >> how can i handle work on a day like today? >> turns out it's a spot for honda. 26 years later, the grown-up broderick taking a day off from work. making the most of it and reminding adults of his famous rallying cry. >> life moves pretty fast. if you don't stop and look around once in a while, you'll miss it. and still ahead for us, the middle-aged brain. why 53 could be the smartest. if you have high blood pressure, like me,

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finally, some great news about middle age and how to stay sharp. new research about baby boomer

brainpower from abc's lisa stark. >> reporter: the middle age brain is, well, more brainly then we thought it was. >> there's been this revolution in thinking about the brain. >> reporter: particia cohen is the author of a new book about midlife age 40 to 65. >> i'm middle aged. what is my brain great at? verbal ability should be at high now, vocab is one of those things that keep on improving, financial assessment, management, that's at a high. >> reporter: dr. gary small agrees. he studies the aging brain. >> when we reach middle age, there's a sweet spot where our brains cells are actually firing more rapidly than they do when they're younger. >> reporter: here's one of the reasons why -- if you take a closer look at the brain, the cells are constantly communicating, with the help of a insulation called myelin. it turns out that insulation thickens and peaks as you hit middle age, meaning messages in the brain travel faster. that allows the brain to solve complex problems more quickly

and accurately. what does that mean in terms of everyday skills? well, memory peaks around age 45. financial planning skills at age 53. vocabulary not until your 60s or 70s. but how best to stay sharp? the answer may surprise you. it's exercise. >> it will get your heart to pump nutrients and oxygen to your brain cells. chemicals will cause those brain cells to actually sprout out and communicate to each other more effectively. >> reporter: also critical what you eat and how you feel. >> we want to eat a brain healthy diet -- fish, nuts whole grain. we want to manage stress. >> reporter: so take a brisk walk and then relax. >> your brap is really at the top of its game. >> reporter: now, doesn't that ease the mind? lisa stark, abc news, new york. and we hope you take your brainpower to abcnews.com.

we're always there. remember, "nightline" later. and we will see you right back here again tomorrow night. good night. .